This invention relates to reciprocating pumps, and more particularly to a pump of the type comprising a cylinder having a plunger reciprocal therein and an elastomeric seal for the plunger where it extends out of one end of the cylinder for preventing leakage of the material being pumped.
Generally, these seals have been a point of weakness in prior pumps of the type to which this invention appertains, on account of being prone to being damaged particularly in relatively high pressure pumping operations by high pressure of the material in the cylinder and by large pressure fluctuations which result from the reciprocating action of the plunger. Further, build-up and drying out on the plunger of material being pumped may cause the seal to wear out rapidly, particularly when pumping industrial materials such as sealants, adhesives and inks.